Electric motors are used in many areas of technology. For example, electric motors can be used to drive pumps. If the electric motor here is located in an electrically conductive medium, erosion of the material can occur between components which are located in the conductive medium and are at different electrical potentials. This so-called electrolysis effect can lead to an erosion of material from protective layers in the electric motor. As a result, core materials of the electric motor can be exposed and are in turn subjected to further erosion of material through the electrolysis effect and additionally to corrosion by the conductive and corrosive medium.
In order to reduce the electrolysis effect, the electrical resistance of the conductive medium can be increased by influencing the flow path within the conductive medium in such a way that the transportation of material in the medium is reduced. This may be done, for example, by lengthening the effective flow path between the components which are at different potentials, by installing obstacles such as, for example, wall elements. In addition, this can be achieved by reducing the effective flow cross section in the conductive medium by installing narrow passages such as, for example, seals. In addition, the electrolysis effect can be reduced by virtue of the fact that a chronological interruption occurs in the voltage applied to the different components. In this way, there is only a restricted flow of current in the conductive material so that erosion of material is reduced.
In some applications of electric motors it may be appropriate to provide a potential equalization line. This line, can, when considered as a chronological average, not be connected to the same potential as other components of the electric motor.